Precipitator collecting electrode



y 9 R. RAPER PRECIPITATOR COLLECTING ELECTRODE Filed July 14, 1948 Jiig. a. I

- HAR QRAPR INVENEOR Patented July 8, 1952 *Richard Raper, Wheeling-, Wf-Va ass-ignor' to Wheeling SteelCorporaticn; Wheeling, -W; Va.,

1 .a ccrpcration of Delaware 7 Application July 14, 1948, Serial N6. 38,638 I 3 Claims. (01. 183-- '7) This invention relates to precipitator collecting electrodes. It has to do with electrodes for :collecting solid particles removed from gases in electrical precipitators.

" It-is-known thatprecipitator collecting elec-' trodes, which are of sheet form, should be rigid {and flat-and parallel to each other in order to permit of the employment of maximum voltage in the electrostatic field creating electrodes without-arcing across to the collecting electrodes. If the collecting electrodes are not flat localized "projecting-portions of them which extend relatively close to the field creating electrodes may inducearcing'across the gap, necessitating re- .duction of voltage and hence relatively lliefilcient operation. n r

The collecting electrodes should at the same time be strong and rugged to withstand the shocks to which they are subjected. when the particles clinging to them are removed by striking or vibrating them. Q

, I have devised certainnovel forms of precipitator collectingelectrode which are flat,strong and rugged yet light in weight, easily handled and economical to manufacture.

' I "provide a precipitator collecting electrode comprising a plurality of thicknesses of foraminous'metal disposed in substantial parallelism with'space between adjacent. thicknesses, the thicknesses being braced against one another and connected together to form a substantially rigid unit. I desirably employ expanded metal to make the electrode. Theexpanded metal is preferably flattened so thatit becomes in effect cold'jworked foraminous sheet metal I having strands and bonds formingfdiamonds of the iijshapei of the characteristic diamonds of expand- "e'd metal. The expanded metal may be flattened by passing it through a stand of rolls of a cold rolling mill.

My; precipitator collecting electrode preferably comprises two sheets of foraminous -n'1eta1 arranged in generally parallel relationship, at least one of the sheets, having formed therein a plurality of elongated channels projecting in the same direction from the general plane of the sheet with the metal intermediate channels stretched taut to insure flatness of the sheet, the channels engaging the other sheet whereby to space apart the bodies of the sheets, and connecting means connecting the sheets together to form a unit. The connecting means preferably comprise welds at the channels permanently connecting the sheets together. Desirably each of the sheets has formed therein a plurality of 2 elongated channels and the channels of each sheet engage theother sheet.

Other details, objects and advantages of the invention will become apparent as the following description of certajlnpresent preferredembodiments thereof proceeds.

in F

'panded metal.

in the accompanying drawings .1 have shown certain'pre'sent preferred embodiments o'f'the invention in which Figure 1 is a fragmentary plan view of afprecipitator collecting electrode;

' Figure 2 is an edge view of the gure 1; Figure 3 is'an' edge electrode shown view of a modified form "of electrode; and

Figure l is anedge 'vi'ew of a further modified forin'of electrode. p u v Referring first tov Figures 1 and 2,'there' is shown a precipitator collecting.electrodefdesignated generally by reference numeral '2 ',comprising two thicknesses '3 and 3. of flattened-exnessof'metal is a separate sheet, The sheets are arranged in substantial parallelism. jEa'ch sheet has one or more portions deformed toward the other sheet. Sheet 3 is shown as having two parallel generally channel shaped portions 5 deformed'toward sheet '4 and sheet 4 is shown as havingqo'ne generally channel shaped deformed portion 6 extending 'toward'the sheet 3. The channel ii is shown as being halfway be- 7 All of the channels 5 and 6 are of the same depthperpendicular'to the plane of the electrode so that with the sheets lying. flat and parallel with the crests offthe channels 5 in contact with undeformedportions of the sheet 4 the crest of the channels fis'in contact with an undeformed portion of the sheet The electrode may be of any desired sizefand jeac nslheet may have any desired num er of channels.

The channels are preferably formed in press, the channel forming action to some. extent stretching the metal intermediate channels to insure flatness of the sheets. The sheets are braced against each other and connected together to form a substantially rigid unit. The sheets may be connected together in various Ways but I prefer to *Weld them together at the crests of the channels. The welds need not be continuous along the channels and, 'in fact, when expanded metal is employed will not ordinarily be continuous because of the foraminous nature of the metal.

The electrode of Figures 1 and 2 is shown as In the form-shown each thick.

' although the electrode may be framed if desired.

An advantage in not framing the electrode is that when it is unframed there is less horizontal surface area to catch solid particles falling fromv the electrode. When the electrodes are shocked or vibrated to dislodge the particles adhering thereto it is desired that those particles drop free of the electrodes.

Electrodes such as that of Figures 1 and 2 are especially strong due to the cold working of the metal in forming the channels. When fiattened expanded metal is used the sheets are doubly cold worked, first in flattening the expanded metal and second in forming the channels. The channel forming operation not only forms the channels and cold works the metal but also insures complete flatness of the sheet intermediate the channels which is one of the considerations in the formation of precipitator collecting electrodes as above explained.

The welding of the sheets together may be accomplished by any suitable welding procedure such as resistance welding or spot welding. Since both sheets are of the same gage a sound weld is easily formed without inducing substantial stresses in either sheet as is likely to occur when a thin metal member is welded to a comparatively heavy member. Thus my electrodes are unprecedentedly flat, strong, light in weight and long lasting.

The electrode shown in Figure 3 difiers from that of Figures 1 and 2 in thatthe deformed portions of the respective sheets lie adjacent and in contact with one another. In Figure 3 a sheet 311 has deformed channels a and a sheet la has deformed channels to. The channels 511 are spaced apart the same distance as the channels 'Ba and when the sheets are assembled with the channels of each sheet engaging the other sheet the channels of the respective sheets also engage each other as shown. The sheets may be welded together either at the crests of the channels or at the points where the channels of the respective sheets engage each other such as the points I. The electrode of Figure 3 is especially strong and well adapted to withstand shocking or vibration to dislodge particles.

Figure 4 shows another form of electrode having sheets 3b and 4b, the sheet 312 having channels 5b and the sheet 4b having channels 6b. The channels 5b are spaced apart the same distance as the channels 6b and when the sheets are assembled the crests of the channels 5b are brought opposite and in contact with the crests of the channels Sb. Desirably the sheets are weldedtogether where the crests of the channels 5b engage the crests of the channels 6b. With a structure of this type if the distance between the sheets is to be equal to the distance between-the sheets in structures formed accord- 4 ing to Figure 2 or Figure 3 the channels must be of half the depth of the channels of Figures 2 and 3 as in the structure of Figure 4 the spacing apart of the sheets is determined by the sum of the depths of the channels.

While I have shown and described certain present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

I claim:

1. A precipitator collecting electrode comprising two sheets of foraminous metal arranged in generally parallel relationship, at least one of the sheets having, formed therein a plurality of elongated channels projecting in the same direction from the general plane of the sheet with the metal intermediate channels stretched to insure flatness of the sheet, the channels engaging the othersheet whereby to space apart the bodies of the sheets, and connecting means connecting the sheets together to form a unit;

2. A precipitator collecting electrode comprising two sheets of foraminous metal arranged in generally parallel relationship, at least one of the sheets having formed therein a plurality of elongated channels projecting in the same direction from the general plane of the sheet with the metal intermediate channels stretched to insure flatness of the sheet, the channels engaging the other sheet whereby to space apart the bodies of the sheets, and welds at the channels permanently connecting the sheets together. r

3. A precipitator collecting electrode comprising two sheets of foraminous metal arranged in generally parallel relationship, each of the sheets having formed therein a plurality of elongated channels projecting inthe same direction from the general plane of the sheet with the metal intermediate channels stretched to insure flatness of the sheet, the channels of each sheet engaging the other sheet whereby to space apart the bodies of the sheets, and welds at the channels permanently connecting the sheets together.

RICHARD RAPER.

REFERENCES CITED The following references are of record in the file of this patent:

v UNITED STATES PATENTS Number 1 Great Britain Feb. 6, 1939 

